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31 * @Id: curs_addch.3x,v 1.52 2020/03/21 23:47:23 tom Exp @
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43 <H1 class="no-header">curs_addch 3x</H1>
45 <STRONG><A HREF="curs_addch.3x.html">curs_addch(3x)</A></STRONG> <STRONG><A HREF="curs_addch.3x.html">curs_addch(3x)</A></STRONG>
50 </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
51 <STRONG>addch</STRONG>, <STRONG>waddch</STRONG>, <STRONG>mvaddch</STRONG>, <STRONG>mvwaddch</STRONG>, <STRONG>echochar</STRONG>, <STRONG>wechochar</STRONG> - add a character
52 (with attributes) to a <STRONG>curses</STRONG> window, then advance the cursor
55 </PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
56 <STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
58 <STRONG>int</STRONG> <STRONG>addch(const</STRONG> <STRONG>chtype</STRONG> <STRONG>ch);</STRONG>
59 <STRONG>int</STRONG> <STRONG>waddch(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>const</STRONG> <STRONG>chtype</STRONG> <STRONG>ch);</STRONG>
60 <STRONG>int</STRONG> <STRONG>mvaddch(int</STRONG> <STRONG>y,</STRONG> <STRONG>int</STRONG> <STRONG>x,</STRONG> <STRONG>const</STRONG> <STRONG>chtype</STRONG> <STRONG>ch);</STRONG>
61 <STRONG>int</STRONG> <STRONG>mvwaddch(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>int</STRONG> <STRONG>y,</STRONG> <STRONG>int</STRONG> <STRONG>x,</STRONG> <STRONG>const</STRONG> <STRONG>chtype</STRONG> <STRONG>ch);</STRONG>
62 <STRONG>int</STRONG> <STRONG>echochar(const</STRONG> <STRONG>chtype</STRONG> <STRONG>ch);</STRONG>
63 <STRONG>int</STRONG> <STRONG>wechochar(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>const</STRONG> <STRONG>chtype</STRONG> <STRONG>ch);</STRONG>
66 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
68 </PRE><H3><a name="h3-Adding-characters">Adding characters</a></H3><PRE>
69 The <STRONG>addch</STRONG>, <STRONG>waddch</STRONG>, <STRONG>mvaddch</STRONG> and <STRONG>mvwaddch</STRONG> routines put the character <EM>ch</EM>
70 into the given window at its current window position, which is then
71 advanced. They are analogous to <STRONG>putchar(3)</STRONG> in <STRONG>stdio(3)</STRONG>. If the
72 advance is at the right margin:
74 <STRONG>o</STRONG> The cursor automatically wraps to the beginning of the next line.
76 <STRONG>o</STRONG> At the bottom of the current scrolling region, and if <STRONG>scrollok</STRONG> is
77 enabled, the scrolling region is scrolled up one line.
79 <STRONG>o</STRONG> If <STRONG>scrollok</STRONG> is not enabled, writing a character at the lower right
80 margin succeeds. However, an error is returned because it is not
81 possible to wrap to a new line
83 If <EM>ch</EM> is a tab, newline, carriage return or backspace, the cursor is
84 moved appropriately within the window:
86 <STRONG>o</STRONG> Backspace moves the cursor one character left; at the left edge of
87 a window it does nothing.
89 <STRONG>o</STRONG> Carriage return moves the cursor to the window left margin on the
92 <STRONG>o</STRONG> Newline does a <STRONG>clrtoeol</STRONG>, then moves the cursor to the window left
93 margin on the next line, scrolling the window if on the last line.
95 <STRONG>o</STRONG> Tabs are considered to be at every eighth column. The tab interval
96 may be altered by setting the <STRONG>TABSIZE</STRONG> variable.
98 If <EM>ch</EM> is any other control character, it is drawn in <STRONG>^</STRONG><EM>X</EM> notation.
99 Calling <STRONG>winch</STRONG> after adding a control character does not return the
100 character itself, but instead returns the ^-representation of the con-
103 Video attributes can be combined with a character argument passed to
104 <STRONG>addch</STRONG> or related functions by logical-ORing them into the character.
105 (Thus, text, including attributes, can be copied from one place to
106 another using <STRONG><A HREF="curs_inch.3x.html">inch(3x)</A></STRONG> and <STRONG>addch</STRONG>.) See the <STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG> page for val-
107 ues of predefined video attribute constants that can be usefully OR'ed
111 </PRE><H3><a name="h3-Echoing-characters">Echoing characters</a></H3><PRE>
112 The <STRONG>echochar</STRONG> and <STRONG>wechochar</STRONG> routines are equivalent to a call to <STRONG>addch</STRONG>
113 followed by a call to <STRONG><A HREF="curs_refresh.3x.html">refresh(3x)</A></STRONG>, or a call to <STRONG>waddch</STRONG> followed by a
114 call to <STRONG>wrefresh</STRONG>. The knowledge that only a single character is being
115 output is used and, for non-control characters, a considerable perfor-
116 mance gain may be seen by using these routines instead of their equiva-
120 </PRE><H3><a name="h3-Line-Graphics">Line Graphics</a></H3><PRE>
121 The following variables may be used to add line drawing characters to
122 the screen with routines of the <STRONG>addch</STRONG> family. The default character
123 listed below is used if the <STRONG>acsc</STRONG> capability does not define a terminal-
124 specific replacement for it, or if the terminal and locale configura-
125 tion requires Unicode but the library is unable to use Unicode.
127 The names are taken from VT100 nomenclature.
129 <STRONG>ACS</STRONG> <STRONG>ACS</STRONG> <STRONG>acsc</STRONG> <STRONG>Glyph</STRONG>
130 <STRONG>Name</STRONG> <STRONG>Default</STRONG> <STRONG>char</STRONG> <STRONG>Name</STRONG>
131 ---------------------------------------------------------
132 ACS_BLOCK # 0 solid square block
133 ACS_BOARD # h board of squares
134 ACS_BTEE + v bottom tee
135 ACS_BULLET o ~ bullet
136 ACS_CKBOARD : a checker board (stipple)
137 ACS_DARROW v . arrow pointing down
138 ACS_DEGREE ' f degree symbol
139 ACS_DIAMOND + ` diamond
140 ACS_GEQUAL > > greater-than-or-equal-to
141 ACS_HLINE - q horizontal line
142 ACS_LANTERN # i lantern symbol
143 ACS_LARROW < , arrow pointing left
144 ACS_LEQUAL < y less-than-or-equal-to
145 ACS_LLCORNER + m lower left-hand corner
146 ACS_LRCORNER + j lower right-hand corner
147 ACS_LTEE + t left tee
148 ACS_NEQUAL ! | not-equal
150 ACS_PLMINUS # g plus/minus
152 ACS_RARROW > + arrow pointing right
153 ACS_RTEE + u right tee
154 ACS_S1 - o scan line 1
155 ACS_S3 - p scan line 3
156 ACS_S7 - r scan line 7
157 ACS_S9 _ s scan line 9
158 ACS_STERLING f } pound-sterling symbol
160 ACS_UARROW ^ - arrow pointing up
161 ACS_ULCORNER + l upper left-hand corner
162 ACS_URCORNER + k upper right-hand corner
163 ACS_VLINE | x vertical line
166 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
167 All routines return the integer <STRONG>ERR</STRONG> upon failure and <STRONG>OK</STRONG> on success (the
168 SVr4 manuals specify only "an integer value other than <STRONG>ERR</STRONG>") upon suc-
169 cessful completion, unless otherwise noted in the preceding routine
172 Functions with a "mv" prefix first perform a cursor movement using
173 <STRONG>wmove</STRONG>, and return an error if the position is outside the window, or if
174 the window pointer is null.
176 If it is not possible to add a complete character, an error is
179 <STRONG>o</STRONG> If <STRONG>scrollok</STRONG> is not enabled, writing a character at the lower right
180 margin succeeds. However, an error is returned because it is not
181 possible to wrap to a new line
183 <STRONG>o</STRONG> If an error is detected when converting a multibyte character to a
184 sequence of bytes, or if it is not possible to add all of the
185 resulting bytes in the window, an error is returned.
188 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
189 Note that <STRONG>addch</STRONG>, <STRONG>mvaddch</STRONG>, <STRONG>mvwaddch</STRONG>, and <STRONG>echochar</STRONG> may be macros.
192 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
193 All these functions are described in the XSI Curses standard, Issue 4.
194 The defaults specified for forms-drawing characters apply in the POSIX
198 </PRE><H3><a name="h3-ACS-Symbols">ACS Symbols</a></H3><PRE>
199 X/Open Curses states that the <EM>ACS</EM><STRONG>_</STRONG> definitions are <STRONG>char</STRONG> constants. For
200 the wide-character implementation (see <STRONG>curs_add_wch</STRONG>), there are analo-
201 gous <EM>WACS</EM><STRONG>_</STRONG> definitions which are <STRONG>cchar_t</STRONG> constants. Some implementa-
202 tions are problematic:
204 <STRONG>o</STRONG> Some implementations define the ACS symbols to a constant (such as
205 Solaris), while others define those to entries in an array.
207 This implementation uses an array <STRONG>acs_map</STRONG>, as done in SVr4 curses.
208 NetBSD also uses an array, actually named <STRONG>_acs_char</STRONG>, with a <STRONG>#define</STRONG>
211 <STRONG>o</STRONG> HPUX curses equates some of the <EM>ACS</EM><STRONG>_</STRONG> symbols to the analogous <EM>WACS</EM><STRONG>_</STRONG>
212 symbols as if the <EM>ACS</EM><STRONG>_</STRONG> symbols were wide characters. The misde-
213 fined symbols are the arrows and other symbols which are not used
216 <STRONG>o</STRONG> X/Open Curses (issues 2 through 7) has a typographical error for
217 the ACS_LANTERN symbol, equating its "VT100+ Character" to <STRONG>I</STRONG> (capi-
218 tal I), while the header files for SVr4 curses and the various
219 implementations use <STRONG>i</STRONG> (lowercase).
221 None of the terminal descriptions on Unix platforms use uppercase-
222 I, except for Solaris (i.e., <EM>screen</EM>'s terminal description, appar-
223 ently based on the X/Open documentation around 1995). On the other
224 hand, the terminal description <EM>gs6300</EM> (AT&T PC6300 with EMOTS Ter-
225 minal Emulator) uses lowercase-i.
227 Some ACS symbols (ACS_S3, ACS_S7, ACS_LEQUAL, ACS_GEQUAL, ACS_PI,
228 ACS_NEQUAL, ACS_STERLING) were not documented in any publicly released
229 System V. However, many publicly available terminfos include <STRONG>acsc</STRONG>
230 strings in which their key characters (pryz{|}) are embedded, and a
231 second-hand list of their character descriptions has come to light.
232 The ACS-prefixed names for them were invented for <STRONG><A HREF="ncurses.3x.html">ncurses(3x)</A></STRONG>.
234 The <EM>displayed</EM> values for the <EM>ACS</EM><STRONG>_</STRONG> and <EM>WACS</EM><STRONG>_</STRONG> constants depend on
236 <STRONG>o</STRONG> the library configuration, i.e., <STRONG>ncurses</STRONG> versus <STRONG>ncursesw</STRONG>, where the
237 latter is capable of displaying Unicode while the former is not,
240 <STRONG>o</STRONG> whether the <EM>locale</EM> uses UTF-8 encoding.
242 In certain cases, the terminal is unable to display line-drawing char-
243 acters except by using UTF-8 (see the discussion of <STRONG>NCURSES_NO_UTF8_ACS</STRONG>
244 in <STRONG><A HREF="ncurses.3x.html">ncurses(3x)</A></STRONG>).
247 </PRE><H3><a name="h3-Character-Set">Character Set</a></H3><PRE>
248 X/Open Curses assumes that the parameter passed to <STRONG>waddch</STRONG> contains a
249 single character. As discussed in <STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG>, that character may
250 have been more than eight bits in an SVr3 or SVr4 implementation, but
251 in the X/Open Curses model, the details are not given. The important
252 distinction between SVr4 curses and X/Open Curses is that the non-char-
253 acter information (attributes and color) was separated from the charac-
254 ter information which is packed in a <STRONG>chtype</STRONG> to pass to <STRONG>waddch</STRONG>.
256 In this implementation, <STRONG>chtype</STRONG> holds an eight-bit character. But
257 ncurses allows multibyte characters to be passed in a succession of
258 calls to <STRONG>waddch</STRONG>. The other implementations do not do this; a call to
259 <STRONG>waddch</STRONG> passes exactly one character which may be rendered as one or
260 more cells on the screen depending on whether it is printable.
262 Depending on the locale settings, ncurses will inspect the byte passed
263 in each call to <STRONG>waddch</STRONG>, and check if the latest call will continue a
264 multibyte sequence. When a character is <EM>complete</EM>, ncurses displays the
265 character and moves to the next position in the screen.
267 If the calling application interrupts the succession of bytes in a
268 multibyte character by moving the current location (e.g., using <STRONG>wmove</STRONG>),
269 ncurses discards the partially built character, starting over again.
271 For portability to other implementations, do not rely upon this behav-
274 <STRONG>o</STRONG> check if a character can be represented as a single byte in the
275 current locale before attempting call <STRONG>waddch</STRONG>, and
277 <STRONG>o</STRONG> call <STRONG>wadd_wch</STRONG> for characters which cannot be handled by <STRONG>waddch</STRONG>.
280 </PRE><H3><a name="h3-TABSIZE">TABSIZE</a></H3><PRE>
281 The <STRONG>TABSIZE</STRONG> variable is implemented in SVr4 and other versions of
282 curses, but is not part of X/Open curses (see <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG> for
285 If <EM>ch</EM> is a carriage return, the cursor is moved to the beginning of the
286 current row of the window. This is true of other implementations, but
290 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
291 <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG>, <STRONG><A HREF="curs_clear.3x.html">curs_clear(3x)</A></STRONG>, <STRONG><A HREF="curs_inch.3x.html">curs_inch(3x)</A></STRONG>, <STRONG>curs_out-</STRONG>
292 <STRONG><A HREF="curs_outopts.3x.html">opts(3x)</A></STRONG>, <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>, <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>, <STRONG>putc(3)</STRONG>.
294 Comparable functions in the wide-character (ncursesw) library are
295 described in <STRONG><A HREF="curs_add_wch.3x.html">curs_add_wch(3x)</A></STRONG>.
299 <STRONG><A HREF="curs_addch.3x.html">curs_addch(3x)</A></STRONG>
303 <li><a href="#h2-NAME">NAME</a></li>
304 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
305 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
307 <li><a href="#h3-Adding-characters">Adding characters</a></li>
308 <li><a href="#h3-Echoing-characters">Echoing characters</a></li>
309 <li><a href="#h3-Line-Graphics">Line Graphics</a></li>
312 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
313 <li><a href="#h2-NOTES">NOTES</a></li>
314 <li><a href="#h2-PORTABILITY">PORTABILITY</a>
316 <li><a href="#h3-ACS-Symbols">ACS Symbols</a></li>
317 <li><a href="#h3-Character-Set">Character Set</a></li>
318 <li><a href="#h3-TABSIZE">TABSIZE</a></li>
321 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>